Article of manufacture



1941- R. A. CLAWSON 2,251,268

ARTICLE OF MANUFACTURE Filed April 6, 1940 ATTORNEY Patented Aug. 5,-194l UNITED STATES PATENT, I OFFICE 2,251,268 ARTICLE OF MANUFACTURE Robert Arthur Olawson, Wilmington, Del., as-

slgnor to E. I. du Pont de Nemoui's a Company, Wilmington, Del., acorporatlon of Delaware Application April 6, 1940, Serial No. 328,179 1 Claims- (01.66-178) This invention relates to sheer, knit fabrics, such as ladies sheer, knit ,hose, and more particularly it relates to new and improved sheer, knit articles and fabrics which have been knit from single, artificial filaments, or so-called mono-flls.

For a long time silk has dominated the field of ladies fine hosiery. Recently rayon has come into use to a limited extent and quite recently a new synthetic yarn, made from the material known as a synthetic linear polyamide and as disclosed in United States Letters Patent Nos. 2,071,250, 2,071,251, 2,071,253 and 2,130,948 has been used for such purposes. Silk yarn is necessarily a multifllament yarn since each filament is fine and relatively weak. It has been necessary to make hosiery from silk in the gum to the end that the silk gum may protect the filaments until the stocking is ready to be dyed. It has also been the custom to twist the silk filaments together to protect them during processing and use. Twisting imparts to the silk filaments a greater snag resistance; it produces a sheerer stocking; and it modifies the luster of the silk yarn. To impart mechanical elasticity it has been the custom to twist silk further; and since twisting results in a poorly balanced yarn resort has been made to doubling such twisted yarns to produce a balanced thread. Substantially the same procedure has been followed with rayon and other synthetic yarns, although these yarns have found little use in sheer full-fashioned ladies hosiery. In the production of sheer, knit stockings from yarns comprised of artificial filaments, it has been considered essential, heretofore, to use multifilament yarns in-order to obtain the necessary flexibility and softness. Consequent1y.-since hosiery yarns comprised of artificial filaments have always been multifilai'nent yarns, it has been the practice to twist such yarns to accomplish the same general results as for silk'yarns. Prior to the present'invention, therefore, all sheer, knit'hosiery, and similar sheer, knit structureshave been constructed from multifilament,

twisted yarn. In spite of the twisting, the strength of the yarn is still a function of the strength of the filaments; and since these are in themselves fine and delicate, the individual filaments are easily broken and produce an undesirable fuzzy appearance. As one or more filaments in a yarn become broken, additional strain is placed on the remaining filaments and quite frequently these, in turn, become broken resulting in the failureof the yarn, thus causing runs in the stockings. Not only is such previously known hosiery highly susceptible to damage as stated, but these susceptibilities also existin the course of producing the hosiery with the result that the finished article is expensive by reason of 121111? gumber of units of the article discarded as i e or. i

There has been, a long the part of the public for more durable, sheer hosiery; and in spite of very persistent study of the problem, it has not been solved.

Contrary to all prior art operation and practice, it has now been discovered that sheer, knit hose, and similar sheer, knit goods can be constructed of mono-fils, which knitgoods will have a flexibility, softness and elasticity that for all practical. purposes and 1 usage is hardly distinguishable from previously known multifilament sheer, knit goods of equal strength and durability. The sheerness and durability of monofil sheer, knit goods exceed that of multifilament sheer, knit goods.

It is therefore an object of the present invention to produce new and improved sheer, knit articles and fabrics, such as sheer, knit hose and hosiery fabrics, from artificial mono-fils, which articles and fabrics have great sheerness, strength, elasticity, exceptional durability, and very satisfactory flexibility, softness, and appearance.

articles and fabrics, such as sheer, knit hose and hosiery fabrics from artificial mono-fils of synthetic linear polyamides, which articles and fabrics have great sheerness, strength, elasticity, exceptional durability, and very satisfactory fiexibility, softness, and appearance.

Other objects of the invention will appear hereinafter.

In its broad aspects, the objects of the invention may be accomplished by knitting sheer stockings, and similar articles and fabrics from mono-fils, which have the proper characteristics of denier, tenacity, modulus of elasticity, and

Tenacity Modulus of elasticity I as hereinafter more fully described.

The more specific objects of the invention may best be accomplished by knitting sheer stockings and similar articles and fabrics from mono-fils of synthetic linear polyamides which have the established on proper characteristics of denier, tenacity, modulus of elasticity, and r Tenacity Modulus of elasticity as hereinafter described.

The details of construction of the sheer knit structure of the present invention will be more clearly apparent by reference to the following description taken in-connection withthe accompanying illustrations in which: V

Figure 1 is a side-elevational view showing generally the construction of ladies sheer knit hosiery.

Figure 2 is a magnified view of a smalrsection of a sheer knit structure knitted from single filaments, or mono-fils.

Figure 3 is a very highly magnified view of a small section of a sheer knit structure knitted in the conventional construction from a multiknit stockings from mono-flis in accordance with the present invention. The invention is, of course, 'not to be limited by the specific details of these: examples. 7

Example I Polyhexamethylene adipamide was spun from melt in a manner known to the art to produce monofils-of 60 denier. These mono-fils were cold drawn approximately '40Q%- (ratio drawn; undrawn 4:1) to produce an oriented mono-fii of .15 denier. The mono-fil had a dry tenacity at 75 F. and a relative humidity of 85%.01' 4.8

grams per denier; a residual elongation of 34%,-

a modulus of elasticity of 0.25 gram per denier for a 1% stretch, and a Tenacity Modulus of elasticity factor of 19.2. This mono-filwas knit into a 45-gauge full-fashioned stocking fabric, looped and seamed. The stocking was pre-set by a preboarding process such as is described in United States Letters Patent No; 2,157,119, dyed in a conventional manner, and finally reboarded to finish the stocking.

Example II A 17-denier drawn mono-fil with a dry tenacity at 75 F. and a relative humidity of 65% of 4.8 grams per-denier, a residual elongation of 34%, a modulus of elasticity of 0.25 gram per denier for a 1% stretch, and a Tenacity Modulus of elasticity factor of 19.2, prepared from polyhexamethylene adipamide as in Example I, was knit into a 45- gauge seamless stocking. The stocking was preset by a pre-boarding process, dyed, and finally reboarded. 1 I

The stockings of the examples had a surprisingly good hand and softness, were quite sheer, presented a good appearance, and were very snag resistant. They had good elastic properties, high wet strength, great resistance to the action of water, great heat resistance, and good recovery after deformation while wet or dry because of the ability of the fabric to be set by steam'treatment.

Stockings produced in accordance with the examples given above were more sheer than stockings knit from denier or 17 denier multifilament yarns, respectively; for the compact structure of the mono-iii produces a more sheer appearing fabric than does a multifil of the same denier. I

These stockings, furthermore, even though they were constructed of mono-fils of only 15 or 17 denier,'had a snag resistance as great or greater than that of a stocking knit in a similar manner from a 30 denier multifilament yarn. Furthermore, it was found that when a filament did break, it was more difficult for a run to start. The great strength of v-the synthetic polyamide mono-fil issuch that when it is snagged, the mono-fil is pulled out to such an extent as to cause a tightening of the stitches around the pulled mono-ill before breakage of the mono-fll occurs. This prevents the loose ends from slipping back and permitting a run to occur. This is especially true of synthetic polyamide stocking fabrics which have been pre-set in accordance with the method described in United States Letters Patent No. 2,157,119. By such a process, the stocking is pre-set by subjecting it to a. hot, wet treatment to set the polyamide filaments in the desired shape and loop arrangement preferably by fitting the stocking on a boarding form and treating it with steam. This procedure introduces a set into the multifilament yam, or, in accordance with the present invention in the mono-fil, which ispermanent for all practical purposes, for the usual processes of dyeing, laundering, etc., do not remove the set.

Stockings produced in accordance with the examples present a good appearance. They have good clinging quality and very good elastic properties, especially in view of the fact that the mono-fil is not twisted. But, most surprising of all, these stockings have a remarkably soft hand. One would expect that astocking made from mono-fils would be very stiff, for mono-fils have been used heretofore for purposes requiringstiflness; e. g., in the manufacture oftoothbrush bristles, paint brush bristles, and bristles for other types -of brushes. Despite this generally recognized, inherent characteristic of mono-fils, the mono-iii sheer stocking fabrics of the examples have a surprisingly desirablesoft hand, great snag resistance, and exceeding sheemess.

Although in the above examples, the stocking fabricswere made of mono-fils of 15 and 17 denier, it is to be understood that use may be I made of mono-fils of other denier values, preferably within the limits of 5 to 30 denier, and particularly good results are obtained with monofils of denier values between 10 and 20.

The examples disclose the use of mono-fils having a. dry tenacity at 75 F. and,65% R. H. of

4.8 grams per denier. However, it is to be understood that yarns of other tenacities may be used, preferably those havinga dry tenacity at 75 F. and 65% R. H. of at least 2 grams per denier, and particularly good results are obtained with yarns having a. similar tenacity of at least 4 grams per denier. Throughout the specification gram per denier for 1 stretch. 1 Although moduelasticity about 0.3 gram per .the name of Vaala) the type reference to "tenacity" means dry tenacity at '15? F. and 65% 3.11. a

The modulus of elasticity of the mono-ills described in the examples was stated to be 0.25

ins of elasticity is usually expressed in terms of pounds per square inch or kilograms oer square centimeter required to produce unit elongation, it has been found to be more convenient, when referring to, yarns, to deflne modulus of elasticity as the number of grams per denier required to stretch the yarn 1% in length. It is to be understood that use may be made of mono-his having other values for the modulus of elasticity than that used in the examples, preferably not to'exceed 0.6 gram per denier for 1% stretch. For example, excellent hose can beprepared from mon -flls spun from aminocaproic acid polymer having a modulus of elasticity of about 0.2 gram per denier for 1% stretch. Good 20 hose can be prepared from mono-illsspun from (modulus of denier for 1% stretch), or from the polymer derived from parabeta-amino-diethyl amino-benzene and sebacic polydecamethylene sebacamide acid (modulus of elasticity about 0.4 gram per denier for 1% stretch), or from the interpolymer prepared by conjointly polymerizing vinyl chloride and vinyl acetate in such a manner as to produce a polymer containing 87% of the chloride (modulus of elasticity about 0.4- gram per denier for 1% stretch). On the other hand, mono-ills spun from a blend of polyhexamethylene adipamide and 10% para-tertiary butyl phenol formaldehyde resin (a composition more particularly described in copending application Serial No. 309,898, filed December 18, 1939, in

are somewhat stiffer (modulus of elasticity about 0.5 gram per denier for 1% stretch) and should be spun in finer deniers' and are less satisfactory for mono-ill hose. The best results are obtained with filamentary materials having moduli of elasticity not greater than 0.30 gram per denier for 1% stretch. The determinations of values for modulus of elasticity, as used in this specification, should be made at V R. H. and F. using a dynamometer of manufactured by Ste. Amedes Etablissements Jules Richard, 25 Rue Melingue, Paris, France, with a rate of loading of 3.7 grams per minute per denier.

As above indicated, mono-ills suitable for use in the production of sheer knit goods should have a tenacity of at least 2 grams per denier, a denier of between 5 and 30, and a modulus of elasticity not to exceed 0.6 gram per denier for 1% stretch. The

Tenacity Modulus of elasticity no factor of a mono-fll is of further great importance. In order to obtain sheer knit goods of great sheerness, strength, elasticity, and durability, and exhibiting very desirable flexibility,

softness, and appearance by the use of monofils, the latter should have a Tenacity Modulus of elasticity methylene adipamide. Mono-ills ofother synlinear vinyl polymers,

, may be knitted from possess the proper characteristics of denier, tenacity, modulus of elasticity and Tenacity Modulus of elasticity Although mono-ills prepared from synthetic linear polyamides are preferred, mono-ills of synthetic linear polyesters, synthetic linear polyethers, synthetic linear polyacetals, synthetic interpolymers of vinyl chloride and vinyl acetate, interpolymers of unsymmetrical dichloroethylene; e.- g., with vinyl esters, acrylic and methacrylic acid esters, and styrene, and other types of synthetic linear polymers and interpolymers may also be used the production of desirable sheer knit goods. It is also within the scope of this invention to prepare'sheer stockings and similar sheer knit goods from mono-ills composed of any filament-forming composition so long as the mono-ills have a denier of between 5 and 30, a strength of at least 2 grams per denier, a modulus of elasticity not to Tenacity Modulus of elasticity factor of at least 6. i

when using synthetic linear polyamide mono-' flls, the mono-ills may be drawn to whatever extent, is desired within the possible limits of drawing of the mono-ills, although they are preferably drawn between (1.5:1 ratio of drawn to undrawn yarn) and 500% (5:1 ratio).

In the examples, no step of sizing the mono-- his was referred to. It is preferred not to size the mono-ills, but it is to be understood that a size or finish. may be applied to the mono-ills if desired.-

Either wet or dry mono-ills may be used in the preparation of the stockings of this invention. Wet knitting of unsized yarn gives a more desirable stocking fabric, for it prevents a distortion of the stitches sometimes ness."

The setting of the'synthetic linear polyamide stockings of this invention, though preferably accomplished in accordance with the mcthoddescribed in United States Letters Patent No. 2,157,119, may be accomplished in other ways; e. g., hanging the stockings in a container and exposing them to steam. However, the invention isnot limited to stockings Or other sheer knit fabrics that have been set.

Sheer knit stockings, or similar sheer knit goods, need not be knitted entirely from monoflls. It is also within the scope of this invention to use other types of fibers and yarns; e. g., silk, viscose rayon, cellulose acetate rayon, cotton, etc., in combination with the mono-ills of this invenknown as "lacition. For example, a stocking may be knitted from mono-fils of a synthetic linear polyamide in the heel and toe and silk in the foot and leg. Or a stocking may be knitted from synthetic linear polyamide mono-ills in the foot and le and cotton in the heel and toe. Or, a stocking mono-ills in the'foot and leg, silk in the welt, and cotton in the heel and toe. It is also within the scope of this invention to use synthetic linear polyamide mono-filsin one part of the stocking and multi-fll yarns of synthetic linear polyamides or other materials in other-parts of the stocking. Also a stocking may be prepared from mono-ills for synthetic linear polyamide a The mono-ills used in accordance with this in-.

vention may contain modifying agents, such as luster-modifying agents, platicizers, pigments and dyes, antioxidants, resins, etc. Inasmuch as mono-ills of the characterhereincourse, be suitable for the production of many soft, flexible woven goods in the production of which only muitifllament yarns have heretofore been used. j

In view of the surprisingly good elasticity, strength, durability, snag resistance, run resistance, flexibility, softness of hand, and good appearance of the monofllament sheer, knit stockings, and similar sheer, knit goods of this invention, it is apparent that an important step 2. A sheer, knit structure comprising knit loops which consist of synthetic linear polyamide mono-ills having a denier of between 5 and 30, a tenacity of at 1east'4 grams per denier, a modulus of elasticity not to exceed 0.3, and a Tenacity Modulus of elasticity factor of at least 10.

, above described are suitable for the production of desirable sheer knit structures, they will, of-

forward has been made in this art. There is less wastage of yarn caused by the brealdng of filaments, for a fairly large mono-ill does not snag so easily as do the numerous small filaments (smaller than the mono-ill) of a multifilament yarn. Furthermore, since mono-ills do not require twisting and sizing as do multifllament yarns, a considerable saving in the cost of production of sheer hosiery and other sheer knit goods results from this invention.

The present invention furnishes to the consumer a hosiery product which is substantially better in strength, durability, snag resistance,

.run resistance, and sheerness than any sheer hosiery made from multifllament yarns available at the present time. These results are accomplished with a yarn of lower denier than yarns at present being used for stockings. While this new type of stocking embodies the above-described improvements, it also has surprisingly good elasticity, flexibility, softness of hand, and appearance. I

As it is evident that many changes and modiflcations can be made in the above-described details without departing from the nature and spirit of the invention,.it is to be understood that the invention is not to be limited to the details 'set forth, except as set forth in the appended claims.

I claim:

1. A sheer, knit structure comprising knit loops which consist of mono-ills having a denier of between 5 and 30, a. tenacity of at least 2 grams per denier, amodulus of elasticity not to exceed 0.6, and a Tenacity m factor of at least 6.

3. A sheer, knit stocking comprising knit loops which consist of mono-flls having a denier of between 5 and 30, a tenacity of at least 2 grams Der derier, a modulus of elasticity not to exceed 0.6, an a Y Tenacity Modulus of elasticity factor of at least 6.

4. A sheer, knit stocking comprising knit loops which consist of synthetic linear polyamide mono-fils having a denier of between 5 and 30, a tenacity of at least 4 grams per demer, a modulus of elasticity not to exceed 0. 3, and a Tenacity Modulus of elasticity factor of at least 10. v

5. A permanently set, sheer, knit stocking com prising knit loops which consist of synthetic linear polyamide mono-ills having a denier of between 5 and 30, a tenacity of atv least 4 grams per denier, a modulus of elasticity not to exceed 0.3 and a Tenacity Modulus of elasticity factor of at least 10.

6. A sheer, knit stocking comprising knit loops which consist of mono-ills of polyhexamethylene adipamide, said mono-fils having a denier of between 5 and 30, a tenacity of at least 4 grams per denier, a modulus of elasticity not to exceed 0.3, and a Tenacity Modulus of elasticity factor of at least 10.

7. A permanently set, sheer, knit stocking comprising knit loops which consist of mono-fils of polyheamethylene adipamide, said mono-fils having a denier of between 5 and 30, a tenacity of at least 4 grams per denier, a modulus of elasa Tenacity Modulus of elasticity factor of at least 10.

ROBERT ARTHUR CLAWSON. 

